Steam reforming of single or multi-component oxygenated feeds could be a viable source of low-carbon hydrogen in the future. Different approaches have been attempted but each has challenges.
One way of generating hydrogen from an oxygenate-containing feed has been to use conventional steam methane reforming technology but to operate at very high temperatures. These temperatures range from 700° C. to about 900° C. However there are disadvantages of operating the steam methane reformer at these high temperatures, such as shorter catalyst lifetime, high capital costs and energy costs due to the high heat involved. Typically this heat is provided by burning natural gas, which produces CO2.
Another method of generating hydrogen has been to use noble metal catalysts such as platinum, palladium and rhodium. By using these noble metal catalysts extreme high temperatures can be avoided; however, the economics of the process can be prohibitively expensive and the processes often require additional external fuel sources or high-pressure steam because of reduced methane and carbon monoxide yields.
Yet another method proposed for generating hydrogen from bio-derived ethanol is to operate the reformer at supercritical water conditions over Ni-based catalysts. However, the very high energy intensity along with expensive metallurgy and fabrication costs required for supercritical reforming of bioethanol due to the very high pressures (>3000 psi) and temperatures greater than 500° C. makes the process less practical at commercial scale.